SL2-S FW 2.0 Highlight weighted exposure metering challenges in backlit scenes

[beewee]

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Has anyone used the highlight weighted exposure metering much? I only started using it recently and noticed some pros and cons.

Pro:

• It does work very well for ensuring that highlights are exposed properly without blowing them out

Con:

• In backlit scenes, the EVF becomes silhouetted and it makes it very difficult to frame/compose accurately
• In backlit scenes, when using iAF/AFs/AFc, because the shadows are so dark, the AF cannot reliably focus accurate on objects in the shadow

I’m starting to think that highlight weighted metering is a great idea for getting proper exposure but it really shouldn’t be applied during framing and AF. It should only really be applied to the actual exposure, just like how the camera only closes down the aperture when the shot is taken and not while framing/composing and focusing.

[michali]

7 hours ago, beewee said:

Has anyone used the highlight weighted exposure metering much? I only started using it recently and noticed some pros and cons.

...........I’m starting to think that highlight weighted metering is a great idea for getting proper exposure but it really shouldn’t be applied during framing and AF. It should only really be applied to the actual exposure, just like how the camera only closes down the aperture when the shot is taken and not while framing/composing and focusing.

I recently acquired an SL2-S as back up to my SL2.  I find the the highlight weighted exposure metering extremely useful. We're in the middle of Southern Hemisphere winter, during which time the days are clear & the light is very bright & harsh. It's presently my standard exposure setting on the SL2-S for wildlife.

Edited July 18, 2021 by michali

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[LocalHero1953]

I don't like it, for the reasons @beeweegives. If I used an auto exposure mode without exposure compensation it might be handy, but I don't - I find it easier to judge exposure with the histogram and EC.

[LikameLeica]

7 hours ago, beewee said:

Has anyone used the highlight weighted exposure metering much? I only started using it recently and noticed some pros and cons.

Pro:

• It does work very well for ensuring that highlights are exposed properly without blowing them out

Con:

• In backlit scenes, the EVF becomes silhouetted and it makes it very difficult to frame/compose accurately
• In backlit scenes, when using iAF/AFs/AFc, because the shadows are so dark, the AF cannot reliably focus accurate on objects in the shadow

I’m starting to think that highlight weighted metering is a great idea for getting proper exposure but it really shouldn’t be applied during framing and AF. It should only really be applied to the actual exposure, just like how the camera only closes down the aperture when the shot is taken and not while framing/composing and focusing.

I have experienced similar challenges with backlit situations.  I do like during walkabout situations during bright days for a lot of situations, but I generally prefer center weighted and then dial in my preferred exposure with Exposure Compensation.  

[Photoworks]

when leica presented it, it was an extra tool, never intended to use in all situations. you probably don't use spot meter all the time either .

[beewee]

5 hours ago, Photoworks said:

when leica presented it, it was an extra tool, never intended to use in all situations. you probably don't use spot meter all the time either .

I get that highlight weighted metering is not suppose to be the do-everything mode but at the same time, where highlight weighted metering benefits most is in high contrast scenes, for which backlit scenes is probably one use case where a highlight weighted metering mode would be most useful but it seems the current implementation fails spectacularly. Not because the metering accuracy is poor (far from it), but because it basically kills your ability to focus regardless whether it’s MF or AF and frame accurately.

With there being so many metering modes, this is moving away from Leica’s principle of sticking to essentials. I would much rather have 1-2 modes that really do work well than more specialized modes that I have to dig through.

A far more better way to address the issue of focusing and framing is to just apply the highlight weighted exposure to the actual image being captured rather than the exposure preview. At minimum, at least make that an option that can be enabled. If that were the case, highlight weighted metering would be very useful and can basically become the de-facto metering mode for anyone shooting DNG only. Just like how multi-field metering would be the ideal mode for someone shooting jpegs for 95% of the time, highlight weighted exposure with the option to avoid applying the setting to the exposure preview would really make it a feature that goes from being useful maybe 50-80% of the time to something I would probably use 99.9% of the time for pretty much everything except astrophotography.

[SrMi]

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I started using highlight-weighted metering recently. However, I often apply EC to approach ETTR metering. Highlight weighted metering gives me a start point from which I adjust my final exposure. Sometimes I use fully manual metering.

[hansvons]

I find shooting higher ISO in high-contrast environments gives some leeway in the highlights when shooting raw. I figure ISO 800 to be working best for high-contrast shots with the SL2-S. 
Such a relatively high ISO selection as "base" or "native" ISO is the best practice in cinematography for the largest DR and delicate texture.

I know that many stills photographers use ISO 100 or even ISO 50 as their "base" ISO, but when doing so, I find the highlights to be in jeopardy all the time and the overall look too clean and inorganic.

I have to investigate the highlights-weighted exposure tool a bit more, but I believe it lowers exposure to such an extent that highlights aren't clipping. There are, of course, situations that naturally exceed even the widest DR, such as reflections and other bright sources (sun, street, lights, etc). My short test gave me the impression that Leica's highlights-weighted exposure overcompensates in such situations. 

Bottom line: I use the regular metering and adjust with the EV wheel one stop or two, or tilt up the camera, half-press the trigger, and expose for the sky.

[Photoworks]

4 hours ago, hansvons said:

I find shooting higher ISO in high-contrast environments gives some leeway in the highlights when shooting raw. I figure ISO 800 to be working best for high-contrast shots with the SL2-S. 
Such a relatively high ISO selection as "base" or "native" ISO is the best practice in cinematography for the largest DR and delicate texture.

Not sure I follow!

You are saying that you get most DR in native ISO. Yes charts seam to support that.

And you are assuming the ISO 800 is the native because in video ISO400 is the starting iso in log? 
in photography the native ISO is 100 in this camera. My understanding is that you already loosing a little of DR at ISO 800 in photos, plus you are introducing more noise from amplification.  To me the only way you save highlights is underexposing and then hope all you shadow can be recovered in software. 

[hansvons]

Hi @Photoworks, I'm not an engineer, nor a knowledgable person in digital imagery science and sensor technology.  But I do know how ISO, DR, texture (noise) and colour saturation work in practice with Arri Alexas and Red cameras that offer an as-pure-as-possible raw workflow. That is, no denoising or amplifying for high ISO performance etc is applied. The log image you get is as unprocessed as possible. From that background, ISO 400-800 seems to be the "base" ISOs. You get a fat, colour-rich picture with a fine texture in a wide dynamic range that protects highlights. But, as usual, it all depends mainly on your exposure habits and the environment you are in. A fat exposed ISO 800 image quite likely receives more light than a thinly exposed ISO 400 picture.

Then there is the dual ISO amplifying scheme that discusses "base" ISO even harder. As it seems, the SL2-S has two amplifying steps, one at ISO100 and one at ISO800. I have no clue what the technical "better" ISO step is, the first at ISO100 or the second at ISO800. I find the texture and highlight roll-off at ISO 800 convincing; others prefer the cleanliness of ISO100. 

Lastly, there seems to be a desire in the stills world of shooting at low and high ISO simultaneously with the same camera/sensor. Today, people expect a sensor to be working with ISO50 and ISO50.000, representing a stretch of 10 stops. It's conceivable that a sensor that has a usable DR of 12-14 stops cannot sensibly deliver great pictures at either ISO with such a stretch. Some amplifying and denoising must kick in to make that happen, which has influence on the image in one way or the other. I'm a purist and keep denoising switched off in Capture One all the time. I like the look of organic texture.

From that perspective, and the fact that the SL2-S' log encoding starts with ISO 400, I guess that IOS 400-800 is the sensor's sweet spot, all things considered, from colour reproduction to texture, to dynamic range.

But I can be completely wrong, of course. Or to put it differently, the "base" ISO is a personal preference.

[SrMi]

3 minutes ago, hansvons said:

Hi @Photoworks, I'm not an engineer, nor a knowledgable person in digital imagery science and sensor technology.  But I do know how ISO, DR, texture (noise) and colour saturation work in practice with Arri Alexas and Red cameras that offer an as-pure-as-possible raw workflow. That is, no denoising or amplifying for high ISO performance etc is applied. The log image you get is as unprocessed as possible. From that background, ISO 400-800 seems to be the "base" ISOs. You get a fat, colour-rich picture with a fine texture in a wide dynamic range that protects highlights. But, as usual, it all depends mainly on your exposure habits and the environment you are in. A fat exposed ISO 800 image quite likely receives more light than a thinly exposed ISO 400 picture.

Then there is the dual ISO amplifying scheme that discusses "base" ISO even harder. As it seems, the SL2-S has two amplifying steps, one at ISO100 and one at ISO800. I have no clue what the technical "better" ISO step is, the first at ISO100 or the second at ISO800. I find the texture and highlight roll-off at ISO 800 convincing; others prefer the cleanliness of ISO100. 

Lastly, there seems to be a desire in the stills world of shooting at low and high ISO simultaneously with the same camera/sensor. Today, people expect a sensor to be working with ISO50 and ISO50.000, representing a stretch of 10 stops. It's conceivable that a sensor that has a usable DR of 12-14 stops cannot sensibly deliver great pictures at either ISO with such a stretch. Some amplifying and denoising must kick in to make that happen, which has influence on the image in one way or the other. I'm a purist and keep denoising switched off in Capture One all the time. I like the look of organic texture.

From that perspective, and the fact that the SL2-S' log encoding starts with ISO 400, I guess that IOS 400-800 is the sensor's sweet spot, all things considered, from colour reproduction to texture, to dynamic range.

But I can be completely wrong, of course. Or to put it differently, the "base" ISO is a personal preference.

All still cameras that I know deliver the best image quality at base ISO.

[Michael Markey]

I`ve found it very useful  ...

[BernardC]

On 7/19/2021 at 3:47 PM, SrMi said:

All still cameras that I know deliver the best image quality at base ISO.

Obviously, I don't know your technique, so correct me if I am wrong.

I've found that people who believe this share two traits: they use ETTR ("expose to the right"), and they value the ability to recover shadows.

There is nothing wrong with either of those traits, at least for stills. For motion work, ETTR means that every shot has a different exposure, which leads to lots of (usually expensive) correction in post. Even then, you'll never get shots to match fully. Your midtones might be the same, but the contrast roll-off in the highlights and shadows will differ.

The issue of shadow recovery is an aesthetic one. Often you want some shadows to go fully black in motion work. Many stills photographers prefer to leave their options open, in case they decide on a different interpretation at a later date.

The basic concept of ETTR is simple. Start at "base/lowest ISO", and decrease the exposure (aka: increase the ISO) so that your brightest highlights do not clip. The end results are surprisingly similar to a shot done with a 400 or 800 ISO base: if you have some strong highlights, you'll need to stop-down by a few stops, which will give you almost the same shutter/aperture combination. The only significant difference is that your highlights are very close to the edge, whereas a cinema-style exposure provides a wider margin. Again, that comes down to time and effort: you never ever want to re-shoot cine work, so you leave some margin for an unexpected highlight/reflection.

These differences in metering philosophies used to take place back in the film days. Large format art photographers (of the Ansel Adams school) preferred spot meters, while cinematographers mostly preferred incident meters (Spectra, Sekonic). Both schools picked a working EI based on their technique. The end result is mostly the same, so you should use the one that works best for you.

[SrMi]

45 minutes ago, BernardC said:

Obviously, I don't know your technique, so correct me if I am wrong.

I've found that people who believe this share two traits: they use ETTR ("expose to the right"), and they value the ability to recover shadows.

There is nothing wrong with either of those traits, at least for stills. For motion work, ETTR means that every shot has a different exposure, which leads to lots of (usually expensive) correction in post. Even then, you'll never get shots to match fully. Your midtones might be the same, but the contrast roll-off in the highlights and shadows will differ.

The issue of shadow recovery is an aesthetic one. Often you want some shadows to go fully black in motion work. Many stills photographers prefer to leave their options open, in case they decide on a different interpretation at a later date.

The basic concept of ETTR is simple. Start at "base/lowest ISO", and decrease the exposure (aka: increase the ISO) so that your brightest highlights do not clip. The end results are surprisingly similar to a shot done with a 400 or 800 ISO base: if you have some strong highlights, you'll need to stop-down by a few stops, which will give you almost the same shutter/aperture combination. The only significant difference is that your highlights are very close to the edge, whereas a cinema-style exposure provides a wider margin. Again, that comes down to time and effort: you never ever want to re-shoot cine work, so you leave some margin for an unexpected highlight/reflection.

These differences in metering philosophies used to take place back in the film days. Large format art photographers (of the Ansel Adams school) preferred spot meters, while cinematographers mostly preferred incident meters (Spectra, Sekonic). Both schools picked a working EI based on their technique. The end result is mostly the same, so you should use the one that works best for you.

My post that you quoted ("All still cameras that I know deliver the best image quality at base ISO.") and all other posts here relate to still photography.

In this context, I assume the best image quality means an image with the least noise.

Do you disagree that base ISO gives the best quality image (regardless of exposure strategy one uses), or are you saying that the difference between base ISO and ISO 400 or 800 is negligible?

What you describe is not the ETTR approach. The idea of ETTR is to start at base ISO and maximize exposure (shutter speed and aperture) without clipping highlights. With automatic metering that occurs with negative or positive EC. Note that ISO is not part of the exposure.

I am not discussing here the advantages and disadvantages of ETTR. If someone wants to discuss it, let's move it to the appropriate forum. Using base ISO does not imply that you should use ETTR as well.

 

[BernardC]

2 hours ago, SrMi said:

What you describe is not the ETTR approach. The idea of ETTR is to start at base ISO and maximize exposure (shutter speed and aperture) without clipping highlights. With automatic metering that occurs with negative or positive EC. Note that ISO is not part of the exposure.

I could have been more clear. As you mention, ETTR starts at base ISO, and then compensates to keep highlights from clipping. In practice, that means decreasing exposure, because your subject would have to be very flatly-lit to justify increasing exposure.

So, if your "base" is ISO 100 (to pick a number from the SL specifications), and you use exposure compensation to add two stops, you end-up with the same aperture/shutter as you would if you exposed at ISO 400 with no EC. The only difference is that your DNG metadata says "ISO 100", therefore your processing software displays it a little darker, and you need to brighten it by two stops to look "right" (as a starting point). You are taking a different path, but you end-up in the same spot.

You should use the technique that you are comfortable with. Generally, ETTR works best if your goal is to create a single final image, and "incident metering" (or whatever people call it) works best when producing groups of images. It's preferred for cinematography, but it's also used by many photographers who deal with multiple images: wedding, portrait, catalogue, fashion, sports, etc.

[hansvons]

4 hours ago, SrMi said:

Note that ISO is not part of the exposure.

I somewhat disagree. Any sensor has a ISO sweet spot in terms of DR, colour reproduction and noise/texture. In the end, a subjective weighting of these components leads you to an ISO number that you may call the "native" or "base" ISO of that particular sensor. In cinema land, eg the Alexa, the Red Monstro or the Venice that is for most cinematographers ISO 800. Even the manufacturers of the mentioned cameras refer to ISO 800 as there "native" ISO of their respective camera. What one believes is the best possible picture from a particular sensor is highly subjective (some don't want to see texture/noise, others want a smooth roll-off in the whites and deep, saturated shadows and like some texture). But regardless, ISO is part of the equation when it comes to exposure. 

Back in the time, when we were shooting on film, the ISO/ASA numbers on the tin was nothing more than a vague message of the film stock manufacturers to their clientele. Many of us rated the stocks differently accordingly to the environment. Kodak's 5298 at ISO/ASA 500 was rarely rated at ISO 500. I rated it mostly at ISO 320. Otherwise the results tended to be too thin when metering with an incident meter, especially in high contrast scenes such as night exteriors. Often, I rated it even up to ISO 200.

Edited July 21, 2021 by hansvons

[hansvons]

@BernardCCan only say it less comprehensively. Thanks!

[Photoworks]

2 hours ago, hansvons said:

Back in the time, when we were shooting on film, the ISO/ASA numbers on the tin was nothing more than a vague message of the film stock manufacturers to their clientele. Many of us rated the stocks differently accordingly to the environment. Kodak's 5298 at ISO/ASA 500 was rarely rated at ISO 500. I rated it mostly at ISO 320. Otherwise the results tended to be too thin when metering with an incident meter, especially in high contrast scenes such as night exteriors. Often, I rated it even up to ISO 200.

not sure why you bring it up! trying to confuse everyone?

Negative film is totally different than digital. You could overexpose neg film 5 stops and still get a good print.

[SrMi]

4 hours ago, hansvons said:

I somewhat disagree. Any sensor has a ISO sweet spot in terms of DR, colour reproduction and noise/texture. In the end, a subjective weighting of these components leads you to an ISO number that you may call the "native" or "base" ISO of that particular sensor. In cinema land, eg the Alexa, the Red Monstro or the Venice that is for most cinematographers ISO 800. Even the manufacturers of the mentioned cameras refer to ISO 800 as there "native" ISO of their respective camera. What one believes is the best possible picture from a particular sensor is highly subjective (some don't want to see texture/noise, others want a smooth roll-off in the whites and deep, saturated shadows and like some texture). But regardless, ISO is part of the equation when it comes to exposure. 

Back in the time, when we were shooting on film, the ISO/ASA numbers on the tin was nothing more than a vague message of the film stock manufacturers to their clientele. Many of us rated the stocks differently accordingly to the environment. Kodak's 5298 at ISO/ASA 500 was rarely rated at ISO 500. I rated it mostly at ISO 320. Otherwise the results tended to be too thin when metering with an incident meter, especially in high contrast scenes such as night exteriors. Often, I rated it even up to ISO 200.

For those interested, this article describes well why ISO is not part of exposure:

The Unbearable Lightness of Mystic "Exposure" Triangle

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Hallo,

Look here: Leica L-Mount

[SrMi]

4 hours ago, BernardC said:

I could have been more clear. As you mention, ETTR starts at base ISO, and then compensates to keep highlights from clipping. In practice, that means decreasing exposure, because your subject would have to be very flatly-lit to justify increasing exposure.

So, if your "base" is ISO 100 (to pick a number from the SL specifications), and you use exposure compensation to add two stops, you end-up with the same aperture/shutter as you would if you exposed at ISO 400 with no EC. The only difference is that your DNG metadata says "ISO 100", therefore your processing software displays it a little darker, and you need to brighten it by two stops to look "right" (as a starting point). You are taking a different path, but you end-up in the same spot.

You should use the technique that you are comfortable with. Generally, ETTR works best if your goal is to create a single final image, and "incident metering" (or whatever people call it) works best when producing groups of images. It's preferred for cinematography, but it's also used by many photographers who deal with multiple images: wedding, portrait, catalogue, fashion, sports, etc.

I am not following.

If I expose at ISO 100 using at 1/100 sec, then at ISO 400 I would need to expose at 1/400 sec instead of 1/100 sec, thus reducing the exposure and increasing noise. When using automatic metering, and I need -2 EC at ISO 100, then I will need -2 EC at ISO 400 as well.

In SL2, and in most other cameras, ISO is not implemented using DNG metadata but in-camera gain amplification.